Mussel-inspired biomaterials: From chemistry to clinic

Abstract

After several billions of years, nature still makes decisions on its own to identify, develop, and direct the most effective material for phenomena/challenges faced. Likewise, and inspired by the nature, we learned how to take steps in developing new technologies and materials innovations. Wet and strong adhesion by Mytilidae mussels (among which Mytilus edulis-blue mussel and Mytilus californianus-California mussel are the most well-known species) has been an inspiration in developing advanced adhesives for the moist condition. The wet adhesion phenomenon is significant in designing tissue adhesives and surgical sealants. However, a deep understanding of engaged chemical moieties, microenvironmental conditions of secreted proteins, and other contributing mechanisms for outstanding wet adhesion mussels are essential for the optimal design of wet glues. In this review, all aspects of wet adhesion of Mytilidae mussels, as well as different strategies needed for designing and fabricating wet adhesives are discussed from a chemistry point of view. Developed muscle-inspired chemistry is a versatile technique when designing not only wet adhesive, but also, in several more applications, especially in the bioengineering area. The applications of muscle-inspired biomaterials in various medical applications are summarized for future developments in the field.

Keywords: biomaterials; biomedical applications; catechol; coacervation; mussel‐inspired chemistry; pyrogallol; wet adhesion.

FIGURE 1

Structure of blue mussel. (a) Different parts and components of the blue mussel and its foot, (b) different parts of the byssal, (c) molecular thread gradients, and (d) SEM image of the plaque adhered to the surface

FIGURE 2

(a) Schematic of various coacervation processes, (b) scheme of adhesive protein coacervation operation, and (c) different types of proteins in byssal plaque

FIGURE 3

Mussel adhesion to the surface at various pH. (a‐1) at pH < 7, MAPs readily transfer to the surface; Lysine and DOPA facilitate the development of bident H bonds and surface oxide coordination interactions. (a‐2) DOPA's auto‐oxidation at the basic region (pH = 7.5–8.2) is an issue that could cause adhesion to reduce by more than 75% or 95% in comparison to low pH such as 3 and 5, respectively. Along with the formation of dopaquinone, catechol oxidase, and redox transfer between DOPA and iron (III) ions, trigger the formation of crosslinks in the plaque,

FIGURE 4

Different positions of threads in various situations

FIGURE 5

Chemical structures of catechols found in human plasma. Cys 5‐S‐cysteinyl, DOPAC 3,4‐dihydroxy phenylacetic acid, DHPG 3, and 4‐dihydroxy phenyl glycol

FIGURE 6

Different interactions between catechol and other moieties

FIGURE 7

Mechanism of catechol oxidation in (a) water and (b) air

FIGURE 8

Schematic of Michael addition and Schiff base reaction can occur between quinone and primary amines,

FIGURE 9

Oxidation of (left) N‐acetyl dopamine and (right) N‐β‐alanyl dopamine

FIGURE 10

Chemical structure of (left) l‐histidine and (right) DOPA‐histidine

FIGURE 11

Raper–Mason pathway for the biosynthesis of melanin

FIGURE 12

Schematic illustration of dopamine quinone methide

FIGURE 13

The crosslinking of catechol quinone in various conditions (ionic, linkage‐type, and covalent)

FIGURE 14

Schematic of Zwitterionic functional groups and one zwitterated siloxane

FIGURE 15

Microgelation of dopamine and zwitterion

FIGURE 16

Synthesis route for trihydroxybenzenes from the benzene ring

FIGURE 17

Correlation between pH in the polymerization process of catechol‐containing polymers and the degree of polymerization (a). Multimer fraction versus time at a 1:1 Fe³⁺:catechol ratio (b)

FIGURE 18

Schematic illustration of polydopamine coating of different substrates and subsequent conjugating of amine molecules (a). Hippocampal neurons are cultured on PDA‐modified substrate (b) and polylysine immobilization PDA (c). Scale bar

FIGURE 19

A different mechanism of (a) catechol group reaction, (b) Polydopamine hydration

FIGURE 20

Representation of preparation of the composition of ε‐poly‐l‐lysine and catechol and its application for tissue engineering

FIGURE 21

Various types of PDA‐coated materials for antimicrobial applications,

FIGURE 22

Mussel‐inspired therapeutic agents for cancer therapy

FIGURE 23

Illustration of reaction between tissue and dopamine functional groups

FIGURE 24

Adhesive strength versus storage modulus for different biomaterials

FIGURE 25

Schematic immobilization of RGD/heparin on dopamine/polytetrafluoroethylene film